1. Field of the Invention
The present invention relates to an image display apparatus and a setting method of an image display apparatus. In particular, the present invention relates to an image display apparatus capable of changing the scanning direction of an image display, and a setting method of the image display apparatus.
2. Description of Related Art
There are some digital cameras provided with liquid crystal display panels fixedly disposed on the back surfaces of their main bodies in order to make it easy to take a photograph. However, since the angles of liquid crystal panel display units are fixed to the main bodies, a user is obliged to perform photographing without visually confirming an object and the configuration thereof in an angle of view in case of performing angled photographing. Consequently, there is a case where an object which the user wants to photograph is beyond a photographing range.
Accordingly, a digital camera equipped with a liquid crystal panel display unit having a variable-angle mechanism was proposed. In such a kind of digital camera, at the time of the angled photographing, the liquid crystal panel display unit can be opened in the horizontal direction from the main body of the camera, and the opened liquid crystal panel display unit can be further rotated in the vertical direction. Consequently, it became possible for the user to confirm an object while taking a photograph by adjusting configuration while looking at the liquid crystal panel display unit.
However, in the state as it is, the display states of an image become inverse between when the liquid crystal panel display unit is reposed in the main body of the camera and when the liquid crystal panel display unit is opened from the main body of the camera and rotated. That is, it is supposed that a normal scan is being performed in the reposed state, so that the liquid crystal panel display unit is scanned from the left to the right in the horizontal direction, and is scanned from the top to the bottom in the vertical direction. In this case, in the state in which the liquid crystal panel display unit has been opened and rotated, the relation of the scanning direction in the horizontal direction and the vertical direction is opposite to that of the normal scan.
Accordingly, in the sate in which the liquid crystal panel display unit is reposed in the main body of the camera, the display direction of the image displayed on the liquid crystal panel display unit is set to be the normal scanning direction. Furthermore, in the state in which the liquid crystal panel display unit has been opened and rotated, the display direction of an image is set to be the scanning directions opposite in the horizontal and vertical directions to those of the normal scanning. Thereby, the display depending on the orientation of the liquid crystal panel display unit has been performed.
However, when the liquid crystal panel display unit has been opened and rotated, the relation between the pixel colors arranged in the horizontal and the vertical directions in the pixel array of the liquid crystal panel display unit and each of the scanning directions is also inverted. At this time, the hue of a screen changes owing to the electric characteristic of the liquid crystal structure, so that human eyes feel that the hue has changed and the brightness of the screen has changed. A technique for generating a selection voltage of a scanning signal according to the display direction of an image so as to change the brightness of a screen when the display direction of the image is switched, has been proposed as a method for improving such a change of the hue (see Japanese Patent Application Laid-Open Publication No. 2000-172233). According to this, even if the hue on a screen has changed when switching the display direction, the brightness which a user feels owing to a change of the hue can be corrected.
However, by the technique disclosed in the above-mentioned publication, both the adjustment of each image signal and the adjustment of the selection voltage of a scanning signal must be performed in response to the switching of the display direction, and consequently a problem in which a circuit becomes complicated owing to the number of adjustment elements arises. Moreover, the change of the hue is not necessarily caused by only the electric characteristic of the liquid crystal structure as disclosed in the publication document, and there is a change caused by the characteristics of a signal processing circuit at the preceding stage, such as the timing of the sample hold of the image signal. In this case, even if the selection voltage of the liquid crystal element itself is adjusted, it is difficult to perform the adjustment of a suitable hue.